Abstract This application seeks funding for the Substance Use and HIV Prevention Research in Minority Communities training program. The program addresses the urgent need for culturally-competent prevention research in racial and ethnic minority communities targeting the intersection of substance use and HIV. The program offers research education and mentoring to social and behavioral prevention scientists who have cultural expertise regarding minority communities and who are initiating innovative programs of research that focus on substance use and HIV-risk-and-prevention topics. This five-year project will provide educational, mentoring and technical assistance to facilitate the development and continuation of innovative substance use and HIV-prevention research in racial and ethnic minority populations by early-career research scientists from the continental United States and Puerto Rico. The program will accomplish these goals via an intensive summer program housed at the Center for AIDS Prevention Studies at the University of California, San Francisco along with cyber-mentoring during the regular academic year. The program's aims are to: 1) assist visiting scientists in identifying and refining innovative theories, concepts, and ideas into clearly articulated programs of research in substance use and HIV-risk prevention; 2) increase the capacity of visiting scientists to conduct multidisciplinary prevention research that targets the links between substance use and other HIV-risk behaviors in racial and ethnic minority communities; 3) provide funding to conduct pilot research that will yield data for presentations at substance use-focused national conferences and provide preliminary data for grant proposals to NIDA; and 4) provide education, mentoring, and technical assistance in the development and submission of research grants to NIDA that focus on substance use, HIV-risk behavior, and HIV prevention. These aims will be met through an intensive six-week summer program of seminars and one- on-one meetings to be held at the UCSF Center for AIDS Prevention Studies as well as provision of funds to conduct a pilot research study. In collaboration with program faculty mentors, visiting scientists will design pilot studies, which they will conduct during the following academic year, and return to CAPS for a second summer to analyze data from their pilot studies. Findings from the pilot studies will be reported at a national substance use research-focused conference, enabling the scientists to obtain extramural feedback on their work and to network with national and international leaders in substance use research and HIV-prevention research. By the third summer the visiting scientist will have obtained extensive feedback on that proposal, revised it, and submitted it for extramural review. The third summer will provide an opportunity to work with faculty mentors in responding to NIH reviewers' comments, further refining the proposal for resubmission, and, for proposals funded on the first submission, providing guidance in the implementation and management of the funded study. During the academic years between the summer training institutes, the program will use cyber-mentoring to support visiting scientists in completing their pilot studies and grant proposals, while providing additional seminars for topics identified by the visiting scientists (e.g., substance use syndemics, sampling hidden populations). The guidance provided by the collaborative research experiences and opportunities for interdisciplinary networking will result in a substantial increase in high quality substance use and HIV-prevention research by scientists studying minority populations in the U.S.